Trying to impose the White House's will on America's immensely powerful and pampered military is one of the toughest tasks any modern president faces.
That's why Barack Obama's nomination for his new secretary of defence — the blunt, combative Republican Chuck Hagel, a Vietnam veteran who has talked openly of cutting the Pentagon's "bloated" budget — promises extraordinary drama even by Washington's increasingly fraught standards.
Even a president revered within the military as one of its own, such as the former general, Dwight Eisenhower, the supreme commander of allied forces during the Second World War, grew exasperated during his eight years in the White House by his inability to impose strategic clarity and budget limitations on America's "military-industrial complex," a term he coined in his farewell address.
The famously hot-tempered Ike fumed over the high command's chronic resistance to spending cuts and nuclear test bans.
His toughest struggle was resisting the Pentagon's wishes to fight "small wars" in places like Vietnam. He knew these wars don't remain small, as his successors so painfully discovered.
Not all U.S. commanders, of course, have resisted civilian control or advocated reckless military action. (Several senior generals, for example, argued strenuously against the Iraq invasion in 2003, a course of action that was more a product of then defence secretary Donald Rumsfeld and the country's civilian leadership.)
But, as an institution, the U.S. military has its own dynamic towards expansion, a dynamic that is exacerbated by fierce inter-service rivalries, which drive commanders to fight for every advantage that can be wrung from a dysfunctional political class.
It is also a dynamic that is bolstered by a cacophonous chorus of congressional allies, media, think-tank hawks and defence lobbyists with bottomless pockets, which makes the battle to control the Pentagon bureaucracy not for the fainthearted, which is where a Chuck Hagel comes in.
Renegade in power?
The president's nomination of Hagel, someone he flirted with as a potential running mate back in 2008, seems to signal that he intends to ratchet up his drive to reshape the country's fighting services — and, in the process, try to reclaim some control over the central government's burgeoning debt.
Hagel has the war record to command respect and enough familiarity with the human cost of combat to resist easy military nostrums of "shock and awe" style victories.
A Republican renegade, a former senator from Nebraska, Hagel first supported President George W. Bush's invasion of Iraq, but later denounced it as a dangerous "roll of the dice." He even opposed the later troop surges in Iraq and Afghanistan.
On another other big issue of the day, Iran, Hagel not only opposes military action against Iran's growing nuclear facilities, but he even disagrees with the current harsh sanctions against the regime.
Most controversially, critics in Congress, including both Republicans and Democrats, view him as weak on Israel and too friendly towards Arab interests; too ready to open talks with enemies of Israel such as Hezbollah.
This is the subject most likely to generate political heat during the confirmation hearings, even as Hagel now makes reassuring comments about the need to stand fast behind Israel. He does insist, however, that it should come "not at the expense of our Arab and Muslim relationships."
A hill to die on
While Hagel's confirmation hearings are not expected to be easy, the betting seems to be that he will pass. Even the staunch pro-Israel lobby seems to have reservations about making too many waves right now, given the backlash the Netanyahu government received after appearing to intervene (unsuccessfully) in the U.S. election.
But while Hagel will undoubtedly be the lightning rod for whatever might come, it is Obama who is setting the direction. And that direction seems to owe a debt to Ike's sense of American purpose.
Obama is even being called an "Eisenhower Democrat," as he draws on centrist Democrats and Republican realists like Gates, Colin Powell and now Hagel for policy and political cover.
What's more, just as Eisenhower struggled to contain the huge expense of the military-industrial complex by favouring covert action by the CIA in places like Guatemala and Iran over larger wars, so Obama has "led from behind" on Libya, while resisting overt intervention in Syria and relying on drone attacks to destabilize terrorist enemies in places like Pakistan and Mali.
At the same time, it remains to be seen what shock tactics will be needed to wrestle down a U.S. defence budget that has nearly doubled since 9/11, consumes almost a quarter of all proposed 2013 federal outlays, and is more than the next 13 big military spenders combined, a list that includes Russia, China, Germany, France and the U.K.
U.S. military spending was nearly $730 billion last year, a figure that includes almost $120 billion for the wars in Afghanistan and Iraq.
But the outgoing defence secretary, Panetta, has agreed to not even $50 billion in annual reductions, while many of the traditional congressional hawks want zero cuts, and, in some cases, even higher spending.
Obama and Hagel are surely well aware that the American public, given its concern over social entitlements like Medicare, is strongly in favour of slashing the military and resisting new military adventures, at least according to opinion polls.
But having "a strong military" is still an article of faith in American politics — a hill to die on, as some previous office holders have found.
As a former Vietnam infantryman, who was wounded twice in action, Hagel has presumably learned how to pick his battles carefully.